Black anodized aluminum. Automatic thermostat bypass valve. The oil flow route will bypass the oil cooler to prevent over-cooling the engine oil. Simple in-oil line installation. The automatic by-pass valve works because the flowing oil will take the path of least resistance and travel across theopen by-pass hole rather than go through the oil cooler. As the oil temperature approaches 185˚F (85°C) theactuator begins to move. By 195˚F (90.6°C) the actuator has fully closes the by-pass hole and directing all the hot oil to the oil cooler. Complete with all necessary hardware and easy-to-follow installation instructions. Note: If the oil hoses between the oil cooler and the oil source are too short; the oil cooler by-pass valve may not fit in the oil lines. This Jagg mini by-pass valve require at least 3" (7.6cm) of straight hose.